The Dred Scott decision, also known as the legal case of Dred Scott v. John F.A. Stanford, is considered by historians as the U.S. Supreme Court's single worst decision ever.
Dred Scott, a slave owned by the Emerson family, moved with the family from Missouri, which was a slave state, to Illinois and Wisconsin. He married Harriet Robinson, who was also working for the household, and they both returned to Missouri with the Emersons. After John Emerson's death, Dred tried to purchase him and his wife's freedom from Emerson's widow, but she refused the sale. This prompted the Scotts to sue for their freedom, as they felt that living in two free states had legally freed them from slavery.
The U.S. Supreme Court ruled on March 6, 1857 that Dred Scot and his wife were not to be freed. It was stated that slaves that resided in free states were not free and that African Americans were not to be considered U.S. Citizens and had no right to sue. The Court also decided that the Missouri Compromise, which declared certain territories free, was unconstitutional. According to historians, this judgement pushed America closer to a civil war.